U.S. patent number 8,282,382 [Application Number 13/274,838] was granted by the patent office on 2012-10-09 for method of manufacturing thermoformed plastic articles and drink cup lid made by such method.
This patent grant is currently assigned to IVMA Holdings Company. Invention is credited to Ivonis M. Mazzarolo.
United States Patent |
8,282,382 |
Mazzarolo |
October 9, 2012 |
Method of manufacturing thermoformed plastic articles and drink cup
lid made by such method
Abstract
A method and apparatus for vacuum thermoforming disposable drink
cups lids. The method and apparatus include the step of imparting
printing to the lids in two or more colors. The step of imparting
printing to the lids is done while the lids are in contact with the
vacuum thermoforming platen.
Inventors: |
Mazzarolo; Ivonis M.
(Vaudreuil, CA) |
Assignee: |
IVMA Holdings Company
(Westmount, CA)
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Family
ID: |
44780022 |
Appl.
No.: |
13/274,838 |
Filed: |
October 17, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120034329 A1 |
Feb 9, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12756244 |
Apr 8, 2010 |
8038432 |
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11583529 |
Oct 19, 2006 |
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10691231 |
Oct 23, 2003 |
7175800 |
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10207595 |
Jul 29, 2002 |
6942832 |
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Current U.S.
Class: |
425/388; 425/343;
425/387.1; 425/540; 425/504; 425/402; 101/329; 101/348;
101/212 |
Current CPC
Class: |
G09F
23/08 (20130101); B65D 47/06 (20130101); B65D
2543/00046 (20130101); G09F 2003/0276 (20130101); B65D
2203/00 (20130101); G09F 2003/0272 (20130101) |
Current International
Class: |
B29C
51/10 (20060101) |
Field of
Search: |
;425/92,302.1,304,342.1,353,356,377,387.1,388,402,451,503,504,538,539,540,4R,817R,122,145,150,DIG.60
;101/35,36,37,212,232,329,348 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Del Sole; Joseph
Assistant Examiner: Malekzadeh; Seyed Masoud
Attorney, Agent or Firm: Carlton Fields, PA Giltinan;
William
Parent Case Text
RELATED APPLICATION
This application is a continuation of U.S. application Ser. No.
12/756,244 filed Apr. 8, 2010, now U.S. Pat. No. 8,038,432, which
is a continuation of U.S. application Ser. No. 11/583,529, filed
Oct. 19, 2006, now abandoned, which is a continuation of
application Ser. no. 10/691,231, filed Oct. 23, 2003, now U.S. Pat.
No. 7,175,800, which is a continuation-in-part of application Ser.
No. 10/207,595, filed on Jul. 29, 2002, now U.S. Pat. No. 6,942,832
and claims priority thereto. The content of the U.S. Pat. Ser. Nos.
11/583,529 and 10/691,231 are incorporated herein by reference.
Claims
What is claimed is:
1. Apparatus for vacuum thermoforming and printing plastic articles
from a substantially continuous web of thermoformable plastic
material comprising: a rotatable vacuum thermoforming drum for
receiving said web and having a continuum of thermoforming dies
defining said articles arranged circumferentially thereon; a vacuum
source associated with said drum; means for providing a web of
thermoformable plastic material at a first elevated temperature to
said drum; means for rotating said drum to cause said web to wrap
partly around said drum and contact said dies while applying vacuum
from said source to said dies; a printing structure carrying a
printing plate and being disposed immediately adjacent said drum at
respective, circumferentially spaced locations for contacting and
imparting ink to plastic articles immediately after said articles
are formed in said web over said dies and while remaining on said
dies at a second elevated temperature; and means for operating said
printing structure in synchronism with the rotation of said
drum.
2. Apparatus of claim 1 wherein said means for operating said
printing structure in synchronism comprises a plurality of gears
and at least one cam.
3. Apparatus of claim 1 wherein said means for operating said
printing structure in synchronism comprises an electronic control
circuit adapted to separately control the rotation speed of said
drum and the rotation speed of said printing structure.
Description
FIELD OF THE INVENTION
This invention relates to the vacuum thermoformed plastic articles
and particularly to a vacuum thermoformed disposable drink cup lid
having printed indicia thereon and a method of manufacturing such
an article.
BACKGROUND OF THE INVENTION
It is well known to manufacture thin plastic articles such as
disposable drink cup lids by vacuum thermoforming. Such articles
are manufactured by causing a web of extruded plastic sheet
material to contact a metal die having the desired shape of the
article formed into a surface thereof. Vacuum is applied to the
platen surface through small holes to draw the plastic material
over the contours of the die. The articles are thereafter cooled,
separated from the web by die cutting, and stacked and/or boxed
using conventional automation devices.
It is also known to vacuum form logos and other indicia on the
plastic lids. Such indicia are typically formed of raised surfaces
in a central deck area of the lid. Because thermoformed plastic
lids are usually of one color, it is difficult to clearly see such
vacuum embossed indicia. To add definition, the raised surfaces of
the embossed indicia may be colored in a secondary operation
carried out by printing machinery separate from the thermoforming
machinery.
BRIEF SUMMARY OF THE INVENTION
According to the present invention, vacuum thermoformed articles
such as disposable drink cup lids are thermoformed and printed;
i.e., provided with coloring on embossed surfaces and/or printed
with logos and other indicia on non-embossed surfaces in what is
essentially a single operation. In other words, printing takes
place as the article is being thermoformed. The invention increases
manufacturing efficiency and lowers manufacturing costs and
provides the end user with added value in the form of marketing and
promotional indicia.
In general, this is accomplished by extruding a thin web of
thermoformable plastic sheet material, contacting the web while hot
with a vacuum thermoforming die configured to form articles such as
disposable drink cup lids having printable areas within the
boundaries of said articles, applying vacuum to form the articles,
immediately thereafter applying ink to the printable areas while
the articles remain in the web and at an elevated temperature and,
thereafter, separating the fully formed and printed articles from
the web. As stated above, the term "printed" is used herein to
refer to both adding color to embossed surfaces and placing indicia
on essentially flat surfaces.
In the preferred form hereinafter described, the method is carried
out by means of an apparatus which comprises a rotating
thermoforming drum carrying a series of plates with die inserts for
forming articles, and a multi-surface rotatable printing cylinder
which rotates in synchronism with the thermoforming drum. The
printing cylinder rotates in synchronism with the drum and with an
Anilox roller which carries ink from a supply to the plates on the
printing cylinder. Synchronism is preferably maintained by gears to
ensure registration between the ink plates and the thermoformed
articles. Fully formed and printed articles thereafter pass to a
conventional die cutter where they are removed from the web. The
articles may be stacked and excess material from the web returned
to the extruder supply hopper.
As described herein, it is possible to print in more than one color
on a surface of the article. This is accomplished by providing two
or more printing mechanisms in angular spaced relationship to the
thermoforming systems, one comprising a printer element which
engages a surface of the article at one point in the thermoforming
process and another printing element which contacts the article for
in-registry printing purposes at another angularly spaced position
in the thermoforming process.
Other applications of the present invention will become apparent to
those skilled in the art when the following description of the best
mode contemplated for practicing the invention is read in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The description herein makes reference to the accompanying drawings
wherein like reference numerals refer to like parts throughout the
several views, and wherein:
FIG. 1 is a schematic view of a system for carrying out the method
of manufacturing disposable drink cup lids;
FIG. 2 is a perspective view of a portion of the machine of FIG.
1;
FIG. 3 is a plan view of a drink up lid made by the inventive
method;
FIG. 4 is a sectional view of the FIG. 3 lid;
FIG. 5 is a plan view of a second lid made by the inventive
method;
FIG. 6 is a sectional view of the FIG. 5 lid; and
FIG. 7 is a schematic diagram of a system for carrying out the
method of manufacturing disposable drink cup lids and printing on
said lids in two different colors.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
First Embodiment
Referring to the drawing, FIG. 1 illustrates in schematic fashion
an apparatus 10 for manufacturing vacuum thermoformed drink cup
lids and simultaneously printing the lids in what is essentially a
single and continuous manufacturing operation. The apparatus 10
comprises a hot melt extruder 12 for receiving ground or pelletized
plastic material such as polystyrene or polyethylene. The extruder
is equipped to melt the plastic material and force it through an
exit die 14 of convention design to produce a thin web 16 of
plastic material. The width of the web may be any desired width;
here approximately 24 inches.
The web 16 exits the extruder die 14 at approximately 320.degree.
F. to 340.degree. F. and passes to a vacuum forming drum 18 which
is suitably mounted for rotation by a drive 22 in either direction
to cause the web to contact forming dies 20 mounted on the drum 18
for the desired time. Coolant and vacuum are applied to the drum by
sources 24 and 26 respectively to control temperatures and to
produce vacuum forming.
After the desired time of contact with the dies 20 on the drum 18
the web 16 with the articles formed therein passes to a die cutter
and stacker 28 of conventional design.
To carry out the printing operation simultaneously and in
synchronism with the thermoforming operation, a printing cylinder
30 is mounted above the drum 18 by means to be described with
reference to FIG. 2. The printing cylinder 30 is equipped with
plates 32 which contact the vacuum formed articles after they have
cooled to a temperature of between about 150.degree.-250.degree.
F., the elevated temperature being effective to rapidly dry the ink
which is applied to the vacuum thermoformed articles by the plates
32 on the printing cylinder 30.
The plates 32 on the printing cylinder 30 are continuously inked by
an Anilox roller 34 which picks up ink 36 from an ink fountain 38
having a filler mechanism 40. Seals and proper ink distribution are
provided by Nylon doctor blade 42 and 44 which form the bottom of
the ink fountain 38 and engage the upper quadrant of the Anilox
roller 34.
The drum 18, printing cylinder 30 and Anilox roller 34 all rotate
in precise synchronism as a result of means hereinafter described
in detail with reference to FIG. 2. In addition the printing
cylinder 30, Anilox roller 34 and ink fountain 38 adapt for
vertical movement by means to be described in order to accommodate
the angular surface of the octagonal thermoforming drum 18.
Referring now to FIGS. 3 and 4 a specific thermoformed article 50
is shown to comprise a thin plastic drink cup lid of approximately
3 V2 inches in diameter and configured to be applied to the upper
rim of a standard plastic or paper disposable drink cup 52. The
specific article 50 shown in FIGS. 3 and 4 is a hot drink cup lid
producing what is known in the trade as a plug fit by means of a
300.degree. channel 54 which is vacuum thermoformed into the
material of the lid 50. A skirt 56 is also vacuum formed around the
periphery of the lid and finally formed by the die cutting
operation carried out by device 28 shown in FIG. 1.
The lid 50 is shown to comprise a drink-through tear-back tab 58
defined by a partially die cut area near the periphery of the lid
and within the discontinuity of the plug fit channel 54. A raised
feature 60 is formed in the lid 50 adjacent a shallow hinge 64 such
that the raised operating feature 60 may be folded back and locked
back into a receiver cavity 62 formed immediately behind the hinge
64. The details of the tear-back/lock-back features of the lid 50
are more fully described in the co-pending application for U.S.
patent application Ser. No. 09/952,144 filed Sept. 14, 2001, the
entire disclosure of which is incorporated herein by reference.
The lid 50 is shown to comprise a large flat central deck area 66
in which there is embossed during the thermoforming operation a
raised logo 68 the features of which have relatively flat raised
surfaces. In accordance with the invention coloring is imparted to
the raised surfaces of the logo 68 by the printing cylinder 30 and
the apparatus of FIG. 1. FIGS. 5 and 6 illustrate a second lid 50'
of a configuration which is slightly different from the
configuration of lid 50. Specifically, the lid 50' has no embossed
logo. Accordingly, the plates 32 of the printing cylinder 30 must
be formed, like conventional rubber stamps, to carry the desired
lettering on other indicia.
Referring now to FIG. 2, the octagonal drum 18, the printing
cylinder 30, the Anilox roller 34 and the ink fountain 38 are shown
in greater detail. A continuous gear surface 74 is formed around
the left peripheral end of the drum 18 with teeth extending
parallel to the axis of rotation of the drum 18. The gear surface
74 is in constant contact with a print cylinder gear 76 which is
mechanically attached to the printing cylinder 30 to rotate the
printing cylinder 30 and the ink plate 32 in precise synchronism
with the rotation of the drum 18 thereby to ensure continuous
registry of the ink plate 32 with the locations of the mold inserts
or dies 20 which are carried by plates 21 attached by machine
screws to the flat surfaces of the drum 18. In this instance there
are three lid forming dies 20 across each of the plates 21 but this
number is merely illustrative. The molding features of the inserts
20 may differ from insert to insert but it is desirable that all of
the inserts be male dies and have essentially the same height so as
to be properly engaged by the printing surfaces of the plates 32.
The feature 60 shown in FIGS. 3 and 4 of the drawings requires that
the ink plates be sized and located to clear the feature 60 as they
engage the top surfaces of the logo 68 during the printing
operation.
The printing cylinder 30 with the associated gear 76 is mounted on
a print head frame 70 which is adapted for pivotal rotation about
an axle 72. Cam rollers 78 mounted on both sides of the frame 70
for rotation relative thereto contact cam surfaces 84 formed on the
drum 18. The cam surfaces are continuous, and, although essentially
octagonal, have machined corners to permit smooth and continuous
contact between the cam surfaces and the associated roller 78. The
clearance between the rollers 78 and the cam surfaces 84 may be
adjusted by means of adjustment screws 88 shown in FIG. 2 to vary
the pressure of the ink plates 32 on the molded plastic articles
during the printing operation.
To ensure a synchronous drive relationship between the printing
cylinder 30 and the Anilox roller 34, the gear 90 is mounted on the
printing cylinder 30 inboard of the gear 76 and meshes with a gear
92 mounted on the left end of the Anilox inking roller 34 as shown
in FIG. 2. The Anilox roller 34 is mounted on the frame 70 by
conventional bearings.
The ink fountain 38 may be adjusted in relationship to the surface
of the Anilox roller 34 by means of a plate 96 which lies between
opposite lateral sections of the frame 70 and carries spacing
adjustment screws 98. The drum 18 is mounted on a frame 100 for
rotation as previously described.
OPERATION
In a typical operation plastic material is forced from the extruder
through the die 14 to form the hot web 16, the web being
continuously drawn from the extrusion die 14 by clockwise rotation
of the drum 18. It will be understood that this drum may rotate in
the counter-clockwise direction if desired to extend the web 16
around the bottom of the drum and thereafter to the die cutter
28.
Substantially as soon as the web 16 encounters the mold inserts 20
of the drum 18 vacuum is applied and the material of the web is
drawn by vacuum over the contours of the dies 20 to form the lids
50 or such other articles as it may be desired in any particular
operation to make. The web material cools to between approximately
140.degree. F. to 250.degree. F. for application of the ink 36 by
way of the plates 32 on the printing cylinder 30. The web material
with the articles now formed therein and printed remains in contact
with the drum 18 and the dies 20 and plates 21 long enough to cool
to between about 70.degree. F. and 110.degree. F. whereupon they
are separated from the drum surface and conveyed to the die cutter
apparatus 28. Extra material from the web not formed into articles
50 may be recovered and ground and returned to the hot melt
extruder 12.
MULTI-COLOR EMBODIMENT
Referring now to FIG. 7, there is shown an apparatus which is
similar to the apparatus of FIG. 1 but which provides the
capability of printing on the surface of the thermoformed articles
in two different colors. Where components of FIG. 7 are identical
to the components of FIG. 1, identical reference numerals are used.
For example, the extruder 12, the die 14, the web 16, the
thermoforming drum 18 with the dies 20, the rotary drive 22, the
coolant source 24 and the vacuum source 26 in FIG. 7 are all
identical to the corresponding components in FIG. 1. Note that,
while an octagonal drum is shown, it is desirable to increase the
size of the drum and increase the number of faces to accommodate
additional colors.
The apparatus of FIG. 1 further comprises a first ink reservoir 101
filled with ink 102 of a first color such as red which supplies red
ink to the Anilox roller 104 which is turn supplies red ink to the
plates 107 on the printing roller 106. Printing roller plates 107
contact the web 16 as it overlies a die 20 on the thermoforming
drum 18 at a first angular position. The first ink reservoir 101
and associated components are, except for position, identical to
the corresponding apparatus shown in FIG. 1.
A second ink reservoir 108 with ink 110 of a second color such as
blue contacts a second Anilox roller 112 which loads the ink onto
the plates 115 of a second printing roller 114. The plates 115
contact the web 16 at a second angular position on the drum 18
which remains in registry with the printing process carried out at
the first position thereby to add a second color to the indicia on
the articles. The printed articles then proceed to the die cutter
28 in the fashion described with reference to FIG. 1. The second
reservoir 108 and associated components are, except for ink color
and position, identical to corresponding components of reservoir
101.
The printing apparatus including the reservoirs 101 and 108 may be
mechanically interconnected for servicing convenience and to ensure
the maintenance of proper registry between the ink plates and the
articles being printed on. The reservoirs, Anilox rollers and
printing rollers may also be supported by means which permit them
to be lifted and withdrawn individually or in unison from the
surface of the web for various purposes which will be apparent to
those skilled in the plastic article printing arts.
While the invention has been described with reference to a specific
article and a specific apparatus for carrying out the manufacturing
method of the article, it is to be understood that it may be
carried out using apparatus of different style and design and also
that articles other than molded plastic drink cup lids may be
manufactured and printed in accordance with the teachings of this
patent. While the adjustable cam rollers and gears described above
with reference to the illustrative embodiment are preferred at this
time, it is to be understood that other and equivalent drive
devices such as belts, chains and the like may also be used to
synchronize the rotation of the various components of the
thermoforming and printing system. Alternatively or additionally a
speed control and synchronization may be achieved electronically
using high resolution encoders and variable speed motors and the
like. A key consideration is to avoid slip between the rotating
drum 18 and the inking cylinders as such slip will deregister the
plates from the articles 50 being printed.
* * * * *